Extension calling unit for telephone



FIG. 1 is a front, top and left side perspective view of an extension calling unit for telephone, showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a rear elevational view thereof; and,

FIG. 7 is a bottom plan view thereof. 

The ornamental design for an extension calling unit for telephone, as shown. 